EP1312405B1 - Filter element for liquid filter of an internal combustion engine, filter comprising such a filter element and vehicle comprising such a filter - Google Patents

Abstract

Filter element (3) has a porous annular side wall extending between two end flanges (17). The first of which has a central hole (18) leading to the interior of the filter and having a collar (30) fitting against a rigid support. The flange is made of a hot-melt thermoplastic resin designed to flow at a temperature of 50-150 degrees C, and the collar projects above its surface of between 0.5-2 mm.

Description

The present invention relates to filter inserts for liquid filters of internal combustion engines, to filters comprising such filter inserts and to vehicles comprising such filters.

More particularly, the invention relates to a filter insert for an internal combustion engine hot-fluid filter, having a porous annular lateral wall which delimits a hollow interior space and which extends along a central axis between two connected end faces of sealed respectively to first and second end flanges sealed, at least the first end flange having a central opening which communicates with the hollow interior space of the filter insert, said first end flange forming an annular bead which surrounds said central opening and which protrudes axially opposite the porous side wall, this bead being adapted to come sealingly against a rigid annular bearing surface.

The document FR-A-2,745,196 (or EP-A-0791387) describes an example of such a filter insert, which gives full satisfaction in terms of its technical operation.

WO 97/26980 also describes an example of such a filter insert, wherein the first flange forming an annular bead can be made of polyurethane or metal.

The present invention is intended to further improve the filter inserts of this type, in particular so that said first plastic flange is better compatible with different types of porous side wall, and in particular with the side walls made of paper or similar pleated with some recumbent folds (e.g. as described in WO-A-99/42199).

For this purpose, according to the invention, a filter insert of the kind in question is characterized in that at least the first end flange consists solely of a hot-melt thermoplastic resin (resin known as "hot melt" by the skilled person) which is adapted to flow under stress from a temperature limit between 50 and 150 ° C.

Thanks to these provisions, the thermoplastic resin flanges are compatible in particular with filter papers or the like folded forming folds folded.

During the use of the filter, at least the bead of the first end plate is deformed by creep so as to exactly match the annular range on which it is applied, as soon as the filter insert is used to filter hot liquid during operation of the internal combustion engine. This provides a perfect and durable seal between the flange and the ring span.

It is remarkable that this seal is obtained without having to reinforce the flange by an insert of felt, cardboard or other, while such inserts would have generally been considered indispensable in the prior art given the creep of the thermoplastic adhesive resin to hot.

• le bourrelet est situé au voisinage de l'ouverture centrale du premier flasque d'extrémité ;
• l'insert filtrant comporte en outre un tube ajouré rigide qui est entouré par la paroi annulaire poreuse dudit insert filtrant et qui s'étend axialement entre les deux flasques d'extrémité, le bourrelet étant disposé dans le prolongement dudit tube ajouré ;
• le bourrelet fait saillie sur une hauteur comprise entre 0,5 et 2 mm par rapport au reste du premier flasque d'extrémité ;
• la résine thermoplastique formant le premier flasque d'extrémité est à base de copolyamide ;
• la paroi latérale annulaire comprend au moins une feuille souple poreuse formant une succession de plis à arêtes axiales, ces plis se présentant, vus en section dans un plan radial, sous la forme d'ailettes incurvées toutes dans un même sens angulaire ;
• les deux flasques d'extrémité de l'insert filtrant sont réalisés dans le même matériau et le deuxième flasque d'extrémité comporte une ouverture centrale entourée par un bourrelet annulaire formé d'une seule pièce avec ledit deuxième flasque d'extrémité et faisant saillie axialement à l'opposé de la paroi latérale poreuse.

In preferred embodiments of the filter insert according to the invention, one or more of the following provisions may also be used:

• the bead is located in the vicinity of the central opening of the first end flange;
• the filter insert further comprises a rigid perforated tube which is surrounded by the porous annular wall of said filter insert and which extends axially between the two end flanges, the bead being arranged in the extension of said perforated tube;
• the bead protrudes over a height of between 0.5 and 2 mm from the rest of the first end flange;
• the thermoplastic resin forming the first end flange is based on copolyamide;
• the annular side wall comprises at least one porous flexible sheet forming a succession of folds with axial edges, these folds being, seen in section in a radial plane, in the form of fins curved all in the same angular direction;
• the two end flanges of the filter insert are made of the same material and the second end flange comprises a central opening surrounded by an annular bead formed in one piece with said second end flange and projecting axially opposite to the porous sidewall.

Furthermore, the subject of the invention is also a hot-liquid filter for an internal combustion engine comprising a rigid housing in which a filter insert is disposed as defined above, the first end flange being pressed against an annular bearing surface. rigid, with sufficient elastic force to cause at least partial crushing of the bead by creep at a temperature between 50 and 150 ° C.

Advantageously, said elastic force is sufficient to further cause partial penetration of the rigid annular bearing into the first end flange out of the bead.

For this purpose, said elastic force may for example be greater than 80 N.

According to one embodiment of the invention, the two end flanges are made of the same material and the second end flange of the filter insert has a central opening surrounded by an annular bead projecting axially opposite. of the porous side wall, the annular bead of the first end flange being applied against a first annular bearing which belongs to the housing of the filter and surrounding a liquid outlet passage in said housing, while the annular bead of the second end flange is in sealing contact with a second annular span belonging to a bypass valve housing, which valve housing by-pass is pressed elastically against the filter insert.

Finally, the invention also relates to a vehicle comprising an internal combustion engine and a filter as defined above for filtering a liquid, said internal combustion engine being adapted to heat said liquid to a normal operating temperature of between 50 and 150 ° C, and said thermoplastic resin being adapted to flow under stress at said normal operating temperature. Advantageously, the filter in question can be an oil filter.

Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings.

• la figure 1 est une vue schématique d'un véhicule comportant un filtre selon la présente invention,
• la figure 2 est une vue en coupe axiale d'un filtre selon une forme de réalisation de l'invention, en cours d'utilisation,
• la figure 3 est une vue partielle en perspective de l'insert filtrant appartenant au filtre de la figure 2, avant usage,
• et la figure 4 est une vue partielle en coupe axiale de l'insert de la figure 3, toujours avant usage.

On the drawings:

• FIG. 1 is a schematic view of a vehicle comprising a filter according to the present invention,
• FIG. 2 is an axial sectional view of a filter according to one embodiment of the invention, in use,
• FIG. 3 is a partial perspective view of the filter insert belonging to the filter of FIG. 2, before use,
• and Figure 4 is a partial view in axial section of the insert of Figure 3, always before use.

In the different figures, the same references designate identical or similar elements.

FIG. 1 represents a motor vehicle V comprising an internal combustion engine M equipped with a filter 1 for filtering a liquid heated by the motor M. The filter 1 can in particular be an oil filter.

As shown in Figure 2, the filter 1 comprises a housing 2 in which is disposed a filter insert 3 replaceable.

The housing 2, which may be made for example of plastic material or another material, comprises a vessel 4 sealed by a cover 5.

The tank 4, which in the example shown has a cylindrical shape of revolution, comprises an annular side wall 6 which extends between an end closed by a bottom 7 and an open end 8 having a thread 9 in which is screwed the cover 5 to close the housing 2.

Note that the cover 5 could be fixed by any other means to the open end 8 of the side wall 6, for example by bayonet mounting, or the like.

Furthermore, the housing 2 comprises a liquid inlet passage 10 and a liquid outlet passage 11. In the example shown, the liquid outlet passage 11 is formed in the center of the bottom 7 and is delimited externally by a annular flange 12 projecting axially inwardly of the housing 2. The liquid inlet passage 10, meanwhile, may be constituted by an orifice in the side wall 6 of the vessel, as in the example shown, but this inlet passage could be provided at any other location of the housing 2, for example in the bottom 7, radially outside the outlet passage 11.

The filter insert 3, which is disposed in the inner volume 13 defined by the housing 2, also has a generally cylindrical shape of revolution in the example shown. This filter insert 3 comprises a porous annular side wall 14 which delimits a hollow interior space 15 and which extends along the central axis Z between two end faces 14a, 14b.

By way of example, as can be seen in FIG. 3, the porous annular lateral wall 14 may comprise a porous flexible sheet (filter paper or the like) forming a series of folds whose edges are parallel to the Z axis. These folds may appear, seen in section in a radial plane, in the form of fins curved all in the same angular direction, inclined relative to the radial direction, as described for example in the document WO-A-99/42199 .

In addition, the porous annular side wall 14 is supported radially inwards by a substantially rigid perforated tube 16 (FIG. 2) which is surrounded by said porous annular lateral wall 14 and which extends axially between the two end faces. 14a, 14b of said side wall.

Each of these end faces 14a, 14b is sealingly closed by an end flange 17 made of thermoplastic resin, which is overmolded on said end face, preferably projecting slightly from this end face radially towards the end face. and radially outwards, and preferably penetrating a few millimeters into said porous annular sidewall 14, in the area 17a visible in FIG.

• l'un des flasques d'extrémité 17 est appliqué avec étanchéité contre une portée annulaire 12a plane et perpendiculaire à l'axe Z, formée par le rebord 12, de façon que l'ouverture 18 de ce flasque d'extrémité fasse communiquer l'espace intérieur 15 de l'insert filtrant avec le passage de sortie 11,
• et l'ouverture centrale 18 du flasque d'extrémité 17 opposé est obturée de façon étanche par le boîtier rigide 19 d'un clapet de by-pass 20, lequel boîtier 19 forme une portée annulaire 21, plane et perpendiculaire à l'axe Z, qui s'applique avec étanchéité contre la face extérieure du flasque d'extrémité 17 autour de l'ouverture centrale 18.

In the example shown, each of the flanges 17 has a central opening 18:

• one of the end flanges 17 is sealingly applied against an annular bearing surface 12a that is flat and perpendicular to the Z axis, formed by the flange 12, so that the opening 18 of this end flange causes the flange to communicate. interior space 15 of the filter insert with the outlet passage 11,
• and the central opening 18 of the end flange 17 opposite is closed sealingly by the rigid housing 19 of a bypass valve 20, which housing 19 forms an annular bearing 21, flat and perpendicular Z-axis, which applies sealingly against the outer face of the end flange 17 around the central opening 18.

A helical spring 22, or any other elastic member, is also interposed between the housing 19 of the bypass valve and the inner face of the cover 5, so as to seal the annular bearing surface 21 of the housing 19 against the flange 17 corresponding and so as to simultaneously apply the opposite flange 17 against the corresponding annular bearing 12a. The spring 22 may for example apply to the filter insert 3 a compression force of between 80 and 200 N, in particular of the order of 100 N.

In the example shown, the housing 19 of the bypass valve is further retained under the cover 5 by clipping, with a certain axial clearance and advantageously allowing relative rotation between the cover 5 and the housing 19. For this purpose , in the example considered here, the housing 19 of the bypass valve comprises a ring 23 projecting axially towards the cover 5 and extended radially outwardly by an annular rim 24 in which clip elastic hooks engage by clipping 25 which extend from the inner face of the cover 5.

Furthermore, in the example shown, the casing 19 of the bypass valve conventionally comprises an orifice 26 which communicates with the internal space 15 of the filter insert and which forms a valve seat 27 normally closed by a valve member. valve 28, which is biased by a spring 29 bearing in the housing 19, so that the bypass valve 20 opens only when there is a pressure difference too high between the upstream and downstream of the filter insert.

Note that, if appropriate, the end flange 17 located towards the cover 5 could possibly be full and do not include a by-pass valve.

According to the invention, the end flanges 17 of the filter insert (or at least the end flange 17 having the central opening 18, if only one of these flanges comprises such an opening) comprise, before assembly of the filter insert in the filter housing 2, an annular bead 30 surrounding said central opening 18 and projecting axially away from the porous annular side wall 14 (see Figures 3 and 4).

As shown in FIG. 4, the bead 30 may for example have a height h of approximately 0.5 to 2 mm, in particular of approximately 1 mm, a width 1 of, for example, between 1 and 3 mm, in particular approximately 2 mm, the bead 30 being preferably in the extension of the perforated tube 16. The end flange 17 also has a thickness e of a few millimeters, for example about 1 to 2 mm, beyond the face corresponding end of the porous annular lateral wall 14.

Finally, the end flanges 17 (or the flange having the opening 18 if only one of the flanges is provided with such an opening) are made of a hot-melt thermoplastic resin ("hot melt"). It may be for example the resin marketed under the trademark "THERMELT 193", sold by the French company TRL. More generally, it is possible to use thermoplastic resins based on copolyamide, preferably having a softening point of between 50 and 250 ° C. (in particular about 200 ° C.) and adapted to flow under stress from a limiting temperature of between 50 and 150 ° C (especially about 100 ° C).

Thus, as can be seen in FIG. 2, when the filter insert 3 is inside the casing 2, at least the beads 30 flatten due to the creep effect due to the relatively high temperature. high oil or filtered liquid heated by the engine (typically of the order of 100 to 150 ° C in the case of oil), under the action of the compression of the spring 22.

This results in an intimate contact between the beads 30 and the corresponding annular bearing surfaces 12a, 21, resulting in excellent sealing around the openings 18 of the flanges 17.

Advantageously, as can be seen in FIG. 2, the aforementioned creep effect may be sufficient to not only crush the beads 30, but also to slightly penetrate the annular bearing surfaces 12a, 21 into the thickness e of the flanges, into areas 17b. This penetration preferably takes place to a depth of a few tenths of a millimeter, generally less than one millimeter.

It will be noted that, despite the aforementioned creep effect, the initial presence of the bead 30 on the end flanges continues to produce an effect even after crushing of said beads and penetration of the annular bearing surfaces 12a, 21 in the flanges 17, creating a annular line having a higher contact pressure between the annular bearing surfaces 12a, 21 and the flanges 17.

Claims (13)

1. Filter element (3) for a hot liquid filter of an internal combustion engine having a porous annular lateral wall (14) which delimits an interior hollow space (15) and which extends according to a central axis (Z) between two end faces (14a, 14b) connected so as to realise a seal in respect of the first and second end caps (17), at least the first end cap having a central opening (18) which communicates with the hollow interior space (15) of the filter element, the first end cap (17) forming an annular bead (30) which surrounds said central opening and projects axially opposing the second end cap, this bead being adapted so as to realise a seal in respect of a rigid annular bearing surface (12a, 21),
   characterised in that at least the first end cap (17) is made solely from a hot adhesive thermoplastic resin which is adapted to flow in a restricted way starting from a limited temperature between 50 and 150°C.
2. Filter element according to claim 1 wherein the bead (30) is situated in proximity to the central opening (18) of the first end cap (17).
3. Filter element according to any one of the preceding claims, also comprising a rigid perforated tube (16) which is surrounded by the porous annular wall (14) of said filter element and which extends axially between the two end caps (17), the bead (30) being arranged in extension of said perforated tube.
4. Filter element according to any one of the preceding claims wherein the bead (30) projects over a height (h) between 0.5 and 2 mm in relation to the rest of the first end cap (17).
5. Filter element according to any one of the preceding claims wherein the thermoplastic resin forming the first end cap (17) has a copolyamide base.
6. Filter element according to any one of the preceding claims wherein the porous annular lateral wall (14) has at least one porous flexible sheet forming a succession of pleats (14c) with axial edges, these pleats being, as seen in section in a radial plan, in the form of vanes which are all bent in the same angular direction.
7. Filter element according to any one of the preceding claims wherein the two end caps (17) of the filter element are realised in the same material and the second end cap has a central opening (18) surrounded by an annular bead (30) formed from a single part with said second end cap and projecting axially opposing the first end cap.
8. Hot liquid filter for an internal combustion engine having a rigid case (2), in which a filter element (3) according to any one of the preceding claims is arranged, the first end cap (17) being pressed against a rigid annular bearing surface (12a, 21), with a sufficient elastic force to bring about at least partial crushing of the bead (30) through flowing at a temperature between 50 and 150°C.
9. Filter according to claim 8 wherein said elastic force is sufficient to also bring about a partial penetration of the rigid annular bearing surface (12a, 21) in the first end cap (17) outside of the bead (30).
10. Filter according to claim 8 or claim 9 wherein said elastic force is greater than 80 N.
11. Filter according to any one of the claims 8 to 10 wherein the two end caps (17) are made from the same material and the second end cap (17) of the filter element have a central opening (18) surrounded by an annular bead (30) projecting axially opposing the porous annular lateral wall, the annular bead (30) of the first end cap (17) being applied against a first annular bearing surface (12a) which belongs to the case (2) of the filter and which surrounds the liquid outlet passage (11) arranged in said case whereas the annular bead (30) of the second end cap (17) realises a seal in respect of the second annular bearing surface (21) belong to a bypass valve case (19) which bypass valve case is pressed elastically against the filter element (3).
12. Vehicle comprising an internal combustion engine (M) and a liquid filter (1) according to any one of the preceding claims 8 to 11, said internal combustion engine (M) being adapted to heat said liquid to a normal operating temperature between 50 and 150°C and said thermoplastic resin being adapted to flow in a restricted way at said normal operating temperature.
13. Vehicle according to claim 12 wherein the liquid filter (1) is an oil filter.

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